We are most grateful for the translations sent to us of Mariska Vermaas' article in the Agarische Dagblad in today's (17th May 2008) Agarisch Dagblad (in Dutch) Link sent by Ruud Peys.

Unborn calves can be infected with BT via the mother

The article states that a cow can pass on the virus to her unborn calf. This comes as a result of research by CVI and GD.

The reason for this research was the export of in-calf cows to NI where calves have been born carrying BT virus. " So far infection of the unborn calf has only occured after vaccination with a life virus vaccine. The BTV8 serotype seems to be somewhat extraordinary" says CVI virologist Piet van Rijn.

The research was carried out on calves from 400 cows born after January, 1st, in the vector free period. 221 cows were antibody positive for BTV8. " In 34 calves, about 15%, born to seropositive dams the virus was detected. The calves were infected in the womb from their dams."

" Maybe during the first time of their lives these calves don't pose a risk transmitting the disease because of antibodies catching the virus. But we don't know what happens once maternal immunity ceases. Maybe these calves constitute a source of the virus for the midges and thus a danger for other animals" says van Rijn.

The whole discussion about overwintering of the virus gets a new dimension

"Vaccination of animals prior to service will minimize the risk of calves born carrying the virus for the following year".

Alternative translation

Unborn calves can become infected with
Bluetongue via the dam

This new finding is the result of an investigtion
by the CVI (Central Veterinary Institute) and GD (Animal Health)

The study was a consequence of the export of
in-calf cows to Northern Ireland which gave birth to calves infected with the
bluetongue virus. The cows were – according to tests – free of the virus. Until
now the transmission (of the virus) to unborn embryos has only been
observed after vaccination with the attenuated Bluetongue virus. This variant of
the Bluetongue serotype 8 seems to be an exception", says CVI virologist Piet
van Rijn. (this doesn't make sense, but is literally translated)

During the investigation the calves of 400 cows
were tested all born after 1 January, the vector free period. 221 cows had
antibodies to Bluetongue. "In 34 claves, approximately 15%, of those cows
(with antibodies) we found the presence of the virus. They got this from
their dams during the pregnancy."

"It is unlikely that the calves will pose a threat
in the spread of the disease during the early part of their lives as the virus
will be caught by the antibodies (this is not well expressed in Dutch but it
is clear that what is meant is that the suckling calf receives the mother's
antibodies) We do not know yet what happens when the maternal protection
ends. It is possible that the calves will form a source of the virus for the
midge and therefore a risk for the rest of the ruminant population", says Piet
van Rijn.

This means that the whole discussion about the
over-wintering ability of the virus takes a new turn. Piet van Rijn:
"Vaccination of animals kept for breeding will reduce the chance of infected
calves during the following season".

Another alternative translation of Mariska Vermaas' article

Unborn
calves can be infected with BT via the mother

research from
the central veterinary institute (CVI) and the health service for animals (GD)
show, reports cattle- and bluetongue - reporter Mariska Vermaas in
Agrarisch Dagblad.

The research
was carried out after calves with the BT-virus were born to pregnant cows
exported to Northern Ireland. The cows themselves had tested virus-free. ''Up
until than, this transfer to the unborn animal had only been found after
vaccination with weakened BT-virusses. The serotype variant of the BT virus
appears to be an exception,'' says viroloog Piet van Rijn from the CVI.In
the course of the research, calves born to 400 cows after 1 January in the
midge-free periods were examined. 221 of the cows had antibodies against
bluetongue. 34 calves were found to have the virus. ''They have got that during
the pregnancy from their mothers,'' Van Rijn says. ''At first, these calves are
probably no danger for the spread of the virus because the virus will be
neutralised by the antibodies. We do not know yet what happens after this
maternal protection stops. It is possible that calves are a source of virusses
for the midges and therefore are a danger for the rest of the cattle.'' Van Rijn
stresses that this gives the whole discussion for overwintering of the virus a
new dimension. ''Vaccinating animals which well be inseminated reduces the risk
of infected calves in the next season.''